http://theanswerpad.com/index.php/go-interactive/ is where you can check out all the details. I heard about it from one o fmy new fave websites Teachnology Tailgate who writes:
The Answer Pad is a free way (1 class per teacher up to 35 students) to use the iPad as an interactive answer sheet. This is great for any T/F, multiple choice, fill in the blank, etc etc type of test or quiz. The teacher uses the web interface to setup their class and get instant real-time results. Plus, everything The Answer Pad does is aligned to state standards.I don't have an ipad, but I have a SMARTboard and my teaching partner next door uses an ipad for everything... I am excited to try our a browser/web version of this when it comes out.
Now, they released their latest update w/ Go Interactive, this basically turns your iPad into a "clicker system". It allows students to answer any question the teacher asks, and they use their iPad to respond, either tap on Y/N, T/F, thumbs up/down, fill in the blank, or draw their answer.